A radical diet

© Illustration | TRUMPF / Markus Weißenhorn

Pressure is growing to achieve more with fewer resources. Suppliers with laser know-how stand to gain

It may sound obvious, but Marko Pfeifer argues that sometimes people need to be reminded of an inescapable fact: “Zero consumption is not a feasible option. If you want to make something, you have to use energy and resources.” As an expert working on the Green Car Body project at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Pfeifer knows what he’s talking about.

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The Green Car Body Project

  • The Green Car Body project stems from the awareness, that current dynamics of exploitation of important mineral resources as well as the significant negative effect on our environment by modern human activity on earth, favour more and more another optimization criterion for production technology: energy and resource efficiency. The project partners set out to research and implement improved and ressource saving manufacturing solutions.

On the companies mentioned

Resource effiziency at TRUMPF

  • At TRUMPF, resource efficiency means highly productive machines designed for highly efficient manufacturing. Even the machines themselves can be produced without waste. Find out more about effiziency+

The project’s goal was to find ways of cutting the amount of energy and resources required to build cars. Pfeifer coordinated the InnoCaT4 sub-project, which investigated the savings potentials in car body production. “But the same process could be applied to a refrigerator or cell phone,” says Pfeifer. The processes might vary somewhat, he explains, but one key finding would, in all likelihood, be the same. “It will only work if the suppliers cooperate,” he emphasizes.

Car body or refrigerator, what’s the difference anyway?

Many companies have direct control over less than half of the energy and resources that go into their final products. As a result, making responsible use of resources inevitably becomes an issue that affects the entire supply chain. The automotive industry is far from being the only example, but it is certainly a context that makes this fact clear at an early stage.

That’s because the automotive sector is a key global industry and an early adopter when it comes to embracing new processes and methods. If automakers decide something is important, the shifts in behavior and technological decisions which follow will affect approaches and investments in companies all over the world.

Zero consumption is not a feasible option. If you want to make something, you have to use energy and resources.

Marko Pfeifer, Fraunhofer IWU

The significance of energy and resource efficiency as a key issue in the industry is illustrated by a presentation given by Ingrid Paulus, senior manager for Green Production at Audi AG in Ingolstadt. She spoke to 270 guests in the auditorium at TRUMPF, an Audi supplier. “We gather data on everything that consumes energy in our production process to see where potentials for improvement lie,” said Paulus. She then listed a number of measures to achieve savings, most of which require the cooperation of suppliers.

Audi’s: It’s all about the details

For example, the body manufacturing facility for the new Audi A3 has combined the welding controller and the welding gun control system into a single unit in order to cut the capital and running costs and to shrink the machine’s footprint. The Audi production engineers have also carefully studied how their robots move and determined that gentle, curved motions require far less energy than abrupt, angular ones.

Paulus also sees significant potential in smart lighting systems: “Robots don’t need light. Only when humans have to intervene is there a need for illumination,” she says. At the same time, intelligent shut-down concepts for both short and long interruptions in the work are playing an increasingly important role in reducing the consumption of energy and consumables. All in all, these methods can save hundreds of megawatts.

We gather data on every user of energy, to find potentials for improvement.

Ingrid Paulus, Audi AG

All these approaches appear in reports issued as part of the Green Car Body project and none of them is specific to any one product. But they inevitably prompt suppliers to find new solutions, some of which will subsequently emerge in other industries.

With the car in the lead, who’s to be next in line?

In 2012, Laser Community published an article on the manufacturing of ovens at Electrolux. EDAG AG developed a laser welding and cutting line for the manufacturer, drawing on its experience with production lines for car makers. This shows clearly that an oven is just another kind of body shell, incorporating a baking cavity. In fact, many job shops are expanding their business using exactly this realization.

It is often dependable and substantial order volumes from the automotive industry that make it possible for firms to invest in modern manufacturing technologies such as 3D laser cutting systems. Once this equipment is installed, the job shop can start to offer laser processing to other customers as well, thus manufacturing their products more efficiently. This process is reinforced by rules laid down by the automakers.

For example, VW insists that agreements with its suppliers incorporate the company’s own standards — intended to minimize environmental impact, promote recyclability and eliminate certain materials. In addition, the VW Group also requires its main suppliers to operate a certified environmental management system in accordance with ISO 14001.

As a result, closely controlled energy and resource consumption is steadily becoming more prevalent among automotive suppliers. Michelfelder Automotive is a good example of this trend. The company’s primary products are stainless steel components for exhaust systems.

Energy-saving concepts, CIP, reducing material waste … we work hard to improve what we do – and we pass on those expectations to our suppliers.

Peter Sohmer, Michelfelder Automotive

Executive director Peter Sohmer explains how they meet repeated customer calls for efficiency increases: “We optimize the systems we use and carefully plan our manufacturing process to optimize machine utilization. We and our customers also agree on tolerance samples to avoid wasting materials. Along with the energy saving concept we have introduced, we have an internal CIP which regularly highlights potential for improvement,” he explains. “We also turn to our suppliers and partners to identify further potential for savings.”

Working on the benefits

The findings and ideas that emerge from this process are then passed along to other companies within the Michelfelder Group, many of which have little or nothing to do with the automotive industry. One of these companies is Michelfelder Metall & Lasertechnik, where the Group’s laser expertise is concentrated. Working as a job shop, it offers its expertise to customers from a wide range of other industries, too.

Another example is Michelfelder Edelstahltechnik. It utilizes the Group’s experience in stainless steel to offer solutions in other industrial sectors such as clean room technology, the food industry, mechanical engineering, and building technology. Werner Huprich, one of the company’s two managing directors, explains their approach: “The automotive industry has no monopoly on high-pressure competition, major technological advances, and customers with very high expectations. We respond by increasing the level of automation and eliminating as many postprocessing and finishing steps as we can. That’s why laser processing, and laser welding in particular, are playing an increasingly important role in our business.”

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Which method requires more energy to make a one-meter cut in five-millimeter sheet steel?

This article holds the solution

Volkswagen looks for the difference in differencial assembly

The fact that laser welding has become one of the key technologies for energy-efficient design is confirmed by welding engineer Holger Fischer. He explains how Volkswagen AG improved the production process for its differential and double clutch assemblies:

“The first step we took was to eliminate the screws and rivets we previously used for fastening, replacing them with laser welding using CO2 lasers and filler material. That reduced component weight by approximately one kilogram,” says Fischer. “In the second stage we switched to disk lasers. These offer almost twice the efficiency and significantly increase process speed.”

Fischer’s second example, the double clutch assembly, has nine joins, all of which are laser welded. All but two of these are butt joints, doing away with the need for flanges and additional material. VW also makes particularly efficient use of its disk lasers, as Fisher explains: “We use laser light guides so that a single beam source can supply multiple welding stations. That cuts out most of the nonproductive stand-by time.”

Laser: by and large the better choice

Making efficient use of the beam source is just one of the many techniques that more than compensate for the laser’s high power consumption, which can initially appear to be something of a handicap when compared to other methods. This becomes even clearer in comparisons that take account of the entire process. For example, Frank Riedel from the Fraunhofer IWU has been working on thermal joining processes in the Green Car Body project.

tlco_infografik_en

The laser boosts efficiency and reduces power consumption, but its greatest strengh lies in the ability to increase productivity.

rejected the idea of using parameters such as power consumption or line energy as a sole measures of comparison. “That approach leaves too many factors out of the equation. So we decided to look at the joining processes as a ‘black box.’ We packed into that box everything you need to join two workpieces over a length of one meter. That included direct energy consumption, the indirect consumption required to prepare the process, post-processing and finishing, process duration, material consumption, space requirements, and so on.”

The team then compared scenarios using different joining processes. Riedel explains what they found: “If you’re looking for the maximum energy efficiency for a particular assembly, then the ideal results will generally be a mix of methods that includes the laser.” Yet this runs counter to a key trend in manufacturing: “Current thinking is that we should be using a smaller number of methods, but more flexibly,” says Riedel. That means there is still plenty of scope for the role of the ultra-flexible laser to evolve.

A dose of efficieny

Even when viewed from the energy and resource consumption perspectives, Riedel argues that the laser has clear advantages over other welding methods. “Obviously you have to melt the material too, but the narrow focus of energy means that the volume fused is extremely small,” he says. That explains why the laser comes out on top in many scenarios even though its wall-plug efficiency lags far behind other processes.

The laser applies its energy to the workpiece extremely efficiently, heating and melting only a minimal, near-ideal volume. And that’s not all, as Riedel explains: “You no longer need to waste energy needed to prepare and close large gaps, to eliminate warping and stress, for straightening or grinding down parts — and in many cases that’s enough to beat other methods when it comes to overall energy efficiency.

The laser comes out on top in many scenarios even though its wall-plug efficiency lags far behind other processes.

Frank Riedel, Fraunhofer IWU

If the laser seams or the laser cuts — depending on the application — serve to create more stable structures from less material, then that boosts the laser’s efficiency rating even higher. This has been confirmed recently in the automotive industry — in the power train, for instance, but also in the high-strength steels used in car body construction.

The thinner sheet metal for the specially designed body components significantly reduces the weight — or the mass — of the materials. This has been made possible by highly productive laser machines which can easily handle this tough material even when dealing with enormous quantities. At the same time, automakers’ efforts to reduce weight and material have opened up new business opportunities for job shops in the sheet steel process chain.

Weld to safe

Similar benefits emerge when lasers are used to extend the service life of components manufactured using large amounts of energy and materials. Repair welding has evolved into a business line in its own right — and Michael Francoeur has been part of this growing trend since the beginning.

In 2005 the American entrepreneur decided to seek maintenance contracts from the aeronautics and aerospace industry for Joining Technologies — his job shop. Cost savings were in the limelight, because this industry uses many highprecision components that are very expensive to produce. Using welding to repair damage, wear, and manufacturing flaws is often considerably cheaper than replacing components completely.

In most cases we can repair components using a fraction of the energy and raw materials that a new part would have required.

Dave Hudson, Joining Technologies

Francoeur’s business partner and CEO of Joining Technologies, Dave Hudson, also points out the sustainable, resource-friendly aspects of his work: “Even though this still isn’t a high priority for many of our customers, it’s worth noting that we generally use only a fraction of the energy and material that would otherwise be required to make a new component.”

Turbine blades and impellers are the most commonly cited examples for this type of repair. But solid shafts and cylinders from large marine diesel engines are also worthwhile candidates which require far more energy and materials to replace than to repair.

Rethinking efficiency

Whichever way you look at it, rethinking energy and resource requirements and the determination to make savings in the use of energy and raw materials are already very prevalent, especially in the intensely cost-conscious automotive industry. “We were originally hoping for potential energy savings of nearly 50 percent,” says Pfeifer. “We didn’t quite achieve that in every research project. But in the end everyone agreed that the savings potentials we had found should be put into practice. It changed the way a lot of people think.” Many suppliers are noticing that change, too — and a growing number are building their futures on it.

Contact: TRUMPF Laser- und Systemtechnik GmbH, Klaus Löffler, Phone +49 (0) 7156 303 – 30962, klaus.loeffler@de.trumpf.com

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